Vitamin D is emerging as a good preventive measure for COVID-19 both to bolster immune response and to dampen the escalating inflammatory response, which can lead to Acute Respiratory Distress Syndrome (ARDS). Vitamin D is one of four fat-soluble vitamins (the others being A, E and K) and it serves as a hormone precursor. Precursors are metabolically inactive. It undergoes two reactions in the body to become active and our kidney makes 1,25OH-D3, which is the biologically active form in the body that functions as a steroid hormone.
How Active Vitamin D is Made in The Body
- UVB light from the sun is absorbed by the skin and converts 7-dehydrocholesterol to Vitamin D3, called cholecalciferol. If you take a D3 supplement, this is the form you are taking – cholecalciferol.
- Vitamin D3 then travels to the liver where it undergoes a hydroxylation reaction and is converted into 25OH-D3, also known as calcifediol. If you test your Vitamin D levels, they test blood levels of 25OH-D3. This is the form used for testing because it has the longest half-life in the body.
- 25OH-D3 then travels to the kidney where it is hydroxylated again to form either: 1) active 1,25OH-D3, also known as calcitriol, which increases blood calcium levels, or 2) active 24,25OH-D3, which decreases blood calcium levels. Whether 25OH-D3 converts to 1,25OH-D3 or 24,25OH-D3 depends on the parathyroid gland, parathyroid hormone and serum calcium levels.
Once active Vitamin D3 is in the blood, it can only start to work after it binds to various proteins such as VDR and GC. Once it binds to the protein, a cascade of action is kicked off that acts on:
- Calcium and phosphorous levels
- Bone mineralization and remodeling
- Dental health
- Innate and adaptive immune response modulation
- Inflammation
- Endocrine, glucose and cardiovascular systems
Binding to VDR and GC is necessary for Vitamin D to do anything in your body. It’s not solely your blood levels of Vitamin D3 that determine if you have enough Vitamin D3; your Vitamin D genetic pathways are also significant.
Genes Involved with Vitamin D Activity
- VDR: Gene for the Vitamin D receptor. It binds with Vitamin D and is involved in regulating inflammation, insulin-like growth factor signaling, estrogen-related pathways, calcium absorption in the stomach and intestines, and bone strength. Gene variants such as having the A allele in VDR has been associated with reduced bone mineral density and osteoporosis.The VDR is also expressed on immune cells such as B cells, T cells and antigen-presenting cells, which means all of these cells are capable of synthesizing the active Vitamin D metabolite. This explains the direct effect Vitamin D has on our immune system. Multiple studies have been done to assess the positive effect of Vitamin D on patients with COVID-19. One study showed that administration of oral 1,25OH-D3 to COVID positive patients resulted in less severity of the disease including reduced rate of ICU admission and reduced mortality.Research found that when Vitamin D binds to VDR, it “may generate beneficial effects on ARDS by decreasing the cytokine/chemokine storm, regulating the renin-angiotensin system, modulating neutrophil activity and by maintaining the integrity of pulmonary epithelial barrier, stimulating epithelial repair and tapering down the increased coagulability.”
- GC: Vitamin D binding protein in the albumin gene family. This protein is found in plasma, cerebrospinal fluid, ascitic fluid and on the surface of many cell types. It binds to Vitamin D and transports it to target tissues. Having a C allele SNP in the GC gene is associated with 49% of increased risk for Vitamin D insufficiency.
- CYP2R1: This is a member of the cytochrome P450 family. It influences conversion of 25OH-D3 to its active form. Having the G-allele SNP in this gene is associated with lower Vitamin D levels because the formation of the active form of D3 is being impacted. CYP21 has been found to be compromised in patients with COPD and asthma.
Checking Your Vitamin D Levels
Concentration of 25OH-D in the serum is the common test for Vitamin D levels. This can be run through a lab or an in-office dried blood spot test. I prefer to use the in-office dried blood spot test as most insurance does not cover Vitamin D testing unless you have a specific diagnosis such as osteoporosis. I like to see Vitamin D levels above 50 ng/ml unless there is autoimmunity in which case I prefer to see Vitamin D between 80-100 ng/ml.
If there is a medical history of osteoporosis, autoimmunity, eczema, being prone to multiple infections, or asthma, I like to look at the Vitamin D genetic pathways. If D3 is not being converted to the active metabolite, or if the Vitamin D related genes have certain alleles that result in reduced binding, the Vitamin D in the blood might not be utilized properly. Also, be aware that there are multiple medications that reduce vitamin D absorption including Cholestyramine, Cimetidine/Tagamet, Colestipol, Corticosteroids (including Prednisone), Heparin, Phenobarbital and Phenytoin.
Ways to Increase Vitamin D Levels
- Sunshine: Vitamin D is known as the sunshine drug! The absolute best way to raise Vitamin D levels is through sun exposure. 30 minutes in the sun around noon time with face, arms and legs exposed to the sun (no sunscreen!) can provide around 8,000IU / day.
- Nutrition: Eating Vitamin D rich foods such as cold water fish (salmon, mackerel, herring), sardines, tuna, halibut, butter, egg yolks, lamb, beef, pork and cod liver oil. Many foods are also fortified with Vitamin D such as milk. Sun-exposed mushrooms have high levels of D2 (ergocalciferol) which can be used to raise Vitamin D levels in the body.
- Supplements: Vitamin D is fat soluble, so taking your Vitamin D supplement with a little bit of fat will increase its absorption.
If you have compromised fat digestion such as gallbladder or pancreatic disease, celiac or IBD, Vitamin D will not be well absorbed in the gut. To bypass that first step of metabolism, I prefer to give Vitamin D supplement in an oil-based, emulsified form. It absorbs directly in the mouth and travels in the blood to the liver to undergo its first hydroxylation.
I recommend 2000-5000 IU/day depending on the individual’s vitamin D levels, symptoms, medical history, genetic profile, medication use, diet, time spent outdoors and time of year. If the patient is severely deficient, I will go up to 10,000 IU/day for several months. I recommend 400-800IU/ day for children. As a naturopathic doctor, I treat the individual and each case is unique. In some cases, it is best to administer Vitamin D together with Vitamin A, Vitamin K and Magnesium.
Please note that because Vitamin D is fat soluble it gets stored in our fat. As a result, toxicity can occur. Special care should be taken by pregnant and lactating women. Please do not self-treat yourself with Vitamin D. Get tested and work with a knowledgeable doctor.
Dr. Tara Tranguch is a naturopathic doctor in Woodbury, CT offering personalized medicine for men, women and children that is natural, effective and transformative. She focuses on preventive health care, digestive issues, environmental medicine, and autoimmunity. Specialized treatments include nutrigenomics, homeopathy and hydrotherapy.
Learn more about naturopathic services at: www.drtaratranguch.com and follow her at: www.facebook.com/drtranguch and https://www.linkedin.com/in/taratranguch/.